In 2001 the FKFS took into operation state-of-the-art 5-belt systems for road simulation in the IVK automotive wind tunnel and in the IVK model wind tunnel. In these systems, a narrow belt running between the vehicles' wheels is fitted with 4 balance-mounted wheel rotation drives and a vehicle restraint system. The FKFS opted for MTS steel belt technology due to its small size and excellent tracking stability. The flat-belt wheel rotation units in the full-scale wind tunnel permit aerodynamic force measurements at full wheel bad up to 70 m/s. In combination with the hydrostatic suspension of these units, integrated force transducers permit realistic measurements of the wheels' rolling resistance. In the model wind tunnel FKFS wheel rotation units with Poly-V belt are used with reduced wheel loads up to 80 m/s. The models' mounting on the balance is carried out automatically for the first time ever by a manipulator designed by WBI. Investigations of the boundary layer, as well as minimization of the boundary layer thicknesses surrounding the vehicle by suction and blowing, combined with the 'block'-profile of the boundary layer above the center belt yielded a good approximation of the situation above a wide 1-belt-system. In combination with boundary layer control, the introduction of road simulation entails increases in aerodynamic drag and decreases of lift. In production cars, added interference of the wheel rotation generally yields reductions of drag. Retroactions from static floor pressures acting on belt surfaces of the wheel rotation units exposed to the test-section floor result in excessively high lift values requiring correction, as opposed to pads with the size of the tire contact area. First approaches are promising.
Die Straßenfahrt-Simulation in den IVK-Windkanälen - Ausführung und erste Ergebnisse
The road simulation in the IVK wind tunnels - design and first results
2003
28 Seiten, 28 Bilder, 20 Quellen
Conference paper
German
Halbmodellmesstechnik in Windkanälen
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